Carbon nanotubes, and nanotubes in general, form a promising substrate for realizing of ultra-clean and locally-tunable electron systems. Contrary to conventional semiconductors, carbon nanotubes have been shown to naturally grow exceptionally clean, leading to low inherent disorder. Nanotubes also possess a collection of desirable physical properties such as: strong electron-electron interactions which can generate correlated electronic ground states, enable localization and individual control over spins and thus realization of a quantum information chain or charge/spin pumps, and interaction of electronic states with mechanical motion of the nanotubes or other correlated materials.
To date, nanotubes' properties have been exploited mostly in zero-dimensional single and double quantum dot settings. The extension to one-dimensional settings (generally utilizing longer effective regions for interactions) has so far been hindered by disorder, which for longer nanotubes, breaks the electronic system into localized, uncontrolled quantum dots. The currently available conventional technologies for producing ultra-clean nanotube devices generally require growth of pristine nanotubes simultaneously with the fabrication of the associated electrical circuit. These two processes are each highly demanding and thus provide limited success in device production which requires both nanotube growing and appropriate circuit fabrication.
Cleanliness of nanotube is generally achieved by setting the growth of the nanotubes as the last step in device fabrication, this limits many design options of the associated circuit due to the high temperatures required for appropriate growth of the nanotubes. Recently, various stamping approaches have eliminated some of these issues by growing the nanotubes separately from the measurement circuit and transferring them mechanically. However, these approaches remain statistical in nature, resulting in effective yield of few percent even for simple devices utilizing short nanotube. Increasing the device complexity with either longer nanotubes or more complex circuits will decrease the yield further, rendering these approaches less practical. Thus, the potential of the nanotube for creating complex locally-tunable electron systems that are electronically pristine remains unrealized.